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Firm vs. Soft Mattresses: All the Pros and Cons

Lara Vargas


Here’s the first question you should answer on your quest for the best mattress: What is better for me, a firm or soft mattress? Of course, each person’s answer will differ depending on their preferences and sleeping needs. And this is exactly why we can’t definitively say firm mattresses are better than soft mattresses, or vice versa—choosing firmness is highly personal.

To help you get an idea about how a mattress will feel before trying it, online bed in a box brands rate their mattress models on a “firmness scale” from one to ten—one being soft and ten being firm. Most mattresses fall between a three and an eight. A mattress rated three is soft against your body, while mattresses ranked 6, 7, and 8 feel firmer.

In this article, we discuss the pros and cons of firm beds and run through everything you need to know to pinpoint the right mattress firmness for your unique sleep needs and preferences. Let’s dive in!

Firm Mattresses

When we hear a mattress is “firm,” we may assume that means it’s hard-as-a-rock and uncomfortable, but this is not the case. Firm mattresses cradle your body ever so slightly but feel notably lifting, as they keep you propped up in a neutral position. Firm mattresses are best at supporting the natural curves and aligning the neck, hips, and legs during stomach and back sleeping.


Let’s start with a worthy sidenote: support and firmness are not the same things. Firm and soft are terms that describe how a mattress feels. Support is all about how the inside of the mattress is put together—and as we all know, it’s the inside that counts! A well-constructed soft mattress is just as supportive as a well-constructed firm mattress.

While both soft and firm mattresses are supportive, the way they support your body is different. This is why soft mattresses are better suited for some sleeping positions, and firm mattresses for others.

Firm mattresses provide a high level of support for back and stomach sleepers because they keep your body weight on top of the mattress. For these sleeping styles, you need some extra reinforcement to maintain the alignment of your shoulders, spine, and hips.

For those who get hot at night and want a more cooling mattress, a firm bed is perfect—it keeps your body “on top” of the mattress, and therefore less insulated. Firm beds are also helpful for those recovering from injuries because their stable surface makes it easier to move around and change positions.

Sleeping Style

As we said above, a firm mattress is especially important for stomach sleepers. When you sleep on your stomach, your hips and belly press into the mattress. A soft mattress cradles your lower torso, and may cause it to sink, placing a lot of strain on your spine. A firm mattress keeps your hips and belly up, aligned with your spine and neck in a neutral position.

Back sleepers also do well with a firm mattress because it maintains the natural curves of their body. As long as your hips are able to sink into the mattress a little bit, your body is in a healthy position.

Body Weight

Firmer mattresses are usually a go-to for sleepers over 250 pounds since they typically want extra support from their bed. These are great mattresses for plus-size back and stomach sleepers, but heavy sleepers wanting a softer mattress should choose medium firmness (or a soft mattress with the right support technologies). Typically, softer mattresses cause uncomfortable sinkage amongst heavier sleepers, but every now and then, you can find one that works for those over 250 pounds.

Best Firm Mattress: Amerisleep AS2

The AS2 is Amerisleep’s medium-firm mattress, perfect for back sleepers, plus-size individuals, and those with back pain.

Take 30% off the AS2

Use code AS30

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Best mattress features
  • Bio-Pur® plant-based foam is more breathable and more responsive than standard memory foam.
  • HIVE® technology provides zoned support to the lumbar spine.
  • Ventilated cover increases airflow to prevent heat-trapping.
Recommended for
  • Back sleepers.
  • Plus-size individuals (those over 230 pounds)
  • Those with back pain.

The AS2 has a Bio-Pur® comfort layer that is firm and supportive to keep the hips and shoulders sinking too far into the mattress and causing the spine to bow. While this foam has less give then their soft model, it still contours to the joints to alleviate pressure and tension so you wake with less pain.

Since Bio-Pur® is made with plant-based oils, this foam is naturally breathable and has more elasticity than standard memory foam. With the help of a ventilated cover, body heat quickly passes through the mattress without causing it to become hot and uncomfortable.

The transition layer of the AS2 features Amerisleep’s Affinity foam with HIVE® technology, a unique zoned support system that promotes spinal alignment and deep relaxation. HIVE® ensures body weight is evenly distributed so the muscles in the back can completely relax and recover during the night. This support system can help those with chronic back pain get a better night’s sleep and wake up feeling refreshed.

The base of the AS2 features Amerisleep’s stable support foam, Bio-Core®. This sturdy material helps guard against premature sagging and soft spots, ensuring sleepers rest in a safe, comfortable position for many years.

The AS2 comes with Amerisleep’s generous 20-year warranty and 100-night sleep trial.

Soft Mattresses

Soft mattresses are excellent at cradling your body and giving your pressure points some much-needed comfort. These beds are cushioning and compress easily beneath weight, but high-quality soft mattresses still offer plenty of healthy support to deter uncomfortable sinking and prevent poor sleep posture. Petite sleepers typically prefer softer beds since they’re plusher against the body, and soft mattresses are excellent for side sleepers and some back sleepers.


Soft mattresses, generally rated 3 on the firmness scale, have ample support for many kinds of sleepers, while providing plenty of cushion to relieve your pressure points. Mattresses inside this range of the scale are ideal for side sleepers because they allow the shoulder and hips to compress—many of the best mattresses for side sleepers are soft to medium in firmness. They’re also great mattresses to relieve arthritis pain since they offer cushion for sensitive areas and sore spots.

Sleeping Style

Soft mattresses are excellent at relieving pressure from your joints, and they are especially good for side sleepers because they contribute to better alignment. Many back sleepers also enjoy soft beds, depending on body weight; average-weight and petite back sleepers may profit from a little extra softness in their bed. With the help of pillows under their lower legs, and a wedge pillow elevating the head, a softer mattress is perfectly comfortable and healthy for back sleeping.

Stomach sleepers have a hard time sleeping in a neutral position on a soft mattress, and this kind of mattress is also not the right choice for anyone over 250 pounds. If you fall into either of these categories, a firmer mattress may be the best fit for you.

Body Weight

Soft mattresses are best suited for light-weight sleepers because they easily conform to the natural lines and curves of your body. Anyone under 250 pounds has no reason to worry about a soft mattress; they can offer plenty of support for your body, and keep you in a neutral position all night long.

Best Soft Mattress: Amerisleep AS5

The AS5 is Amerisleep’s softest, most luxurious mattress, perfect for side sleepers, lightweight individuals, and those with chronic joint pain.

Take 30% off the AS5

Use code AS30

Get discount
Best mattress features
  • Bio-Pur® plant-based memory foam is eco-friendly and non-toxic.
  • Responsive transition layer prevents over-sinking and spinal misalignment.
  • The use of plant-based foam increases breathability.
Recommended for
  • Side sleepers.
  • Lightweight individuals (those 130 pounds or less).
  • Those with chronic joint pain.

The AS5 has an ultra-soft Bio-Pur® comfort layer that cushions and cradles the joints to reduce pressure points when side sleeping. While this material molds to the body for maximum comfort and relaxation, it doesn’t retain heat and moisture the way traditional memory foam does. On the AS5, sleepers remain cool and comfortable.

Soft mattresses can often cause excess sinking which can cause the spine to curve unnaturally during sleep. To prevent this, Amerisleep includes a layer of the Active Flex foam, a highly responsive foam that ensures the hips and shoulders stay lifted and aligned.

A layer of Amerisleep’s Affinity foam with HIVE® technology sits just beneath the Active Flex layer to provide further protection against over-sinking and spinal misalignment. This layer is soft near the joints to prevent pressure points, but firm along the back to promote a healthy spinal position.

The Bio-Core® support foam in the base of the AS5 helps prevent structural changes, such as sagging and indentations. This sturdy base ensures the AS5 will keep you resting in a safe, comfortable position every night.

Like the AS2, the AS5 comes with a 100-night sleep trial and a 20-year warranty.


How do you test a mattress’s firmness?

The best way to test a mattress’s firmness is to take it home and give it a try. Most mattress companies recommend a sleep trial, so you can be sure you are getting the right mattress for your sleep needs. This also gives shoppers the power to buy a mattress online, without leaving the comfort of their own home!

The average length of a sleep trial is 100 nights to a year. We recommend keeping a mattress at least 30 to 60 days before returning or exchanging it because this is how long it takes to properly break it in.

How can you make a mattress softer?

A mattress topper is a great way to adjust the firmness level of your mattress. Toppers cover the entirety of the mattress and are anywhere from one to eight inches thick. We recommend three-inch toppers since these are thick enough to support heavier parts of the body without causing unhealthy sinkage or poor sleep postures.

Is a memory foam mattress good for your back?

For those recovering from a back injury, or consistently having back pain, a memory foam mattress relieves your discomfort and gives you a better night’s sleep. Memory foam cradles your curves and does a great job of alleviating pressure points. We also recommend memory foam mattresses for people experiencing joint pain because of how well they distribute body weight and alleviate pressure.

What makes a mattress firm?

A mattress’s firmness level is based on how it’s made. All mattress types are available in all firmness levels because materials can be modified to have different feels. Things like layer thickness, added pillow-tops, or cushioning materials sewn into the mattress cover can impact firmness, too.

What is the purpose of a box spring?

A box spring provides extra support for your mattress within a bed frame and absorbs motion to lessen wear and tear on your bed. However, they are not used very often anymore because they aren’t compatible with memory foam, latex, hybrids, or any foam beds since they can damage foam layers. While yes, they’re still compatible with innersprings, it’s important to remember that innersprings are being phased out and replaced by hybrids for the most part. With that, we advise looking for solid or slatted bases and durable mattress foundations when shopping for mattress supports.

What Firmness Is Right for You?

When deciding on a mattress, it’s important to find the right firmness level for you personally. Factors to consider are sleeping style, body weight, and what type of support you need. The ultimate factor, however, is what feels most comfortable. Take advantage of the sleep trial and put your new mattress through its paces—make sure it supports your body weight, is comfortable, and helps you sleep soundly. A mattress that checks all of these boxes is a good fit for you!

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